663654621 has 16 divisors (see below), whose sum is σ = 1012427264. Its totient is φ = 378802224.

The previous prime is 663654613. The next prime is 663654623. The reversal of 663654621 is 126456366.

It is not a de Polignac number, because 663654621 - 2³ = 663654613 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 663654621.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (663654623) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1626 + ... + 36468.

It is an arithmetic number, because the mean of its divisors is an integer number (63276704).

Almost surely, 2^663654621 is an apocalyptic number.

It is an amenable number.

663654621 is a deficient number, since it is larger than the sum of its proper divisors (348772643).

663654621 is a wasteful number, since it uses less digits than its factorization.

663654621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 35760.

The product of its digits is 155520, while the sum is 39.

The square root of 663654621 is about 25761.4949294485. The cubic root of 663654621 is about 872.2628462493.

The spelling of 663654621 in words is "six hundred sixty-three million, six hundred fifty-four thousand, six hundred twenty-one".